Replacing 1950s overpasses is costly, complex

SOMERVILLE — How ugly is the McCarthy Overpass, the elevated highway dividing Union Square and East Somerville? Its steel is rusted and flaking, its concrete pockmarked and crumbling. The underside is a lunar landscape of concrete dust, litter, and pigeon droppings.

“It just repels you,” said Hayes Morrison, Somerville’s director of transportation and infrastructure, shuddering at the thought of walking beneath the eroding span, which carries the McGrath Highway (Route 28) over surface streets.